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ICU-trained transport nurse, and on some occasions an ECLS surgeon The inclusion of the surgeon may depend on whether or not the patient is already stable on ECLS, as well as space constraints in the medical transport vehicle.77 Extracorporeal Life Support Simulation High-fidelity ECLS simulation is used in many ECMO centers as a routine part of individual and team training Simulation scenarios typically incorporate team response training, cannulation practice, routine bedside care, circuit and patient troubleshooting, and the response to life-threatening crises on ECLS.78 Recent evidence has demonstrated that ECLS simulation training is effective and superior to traditional ECLS training.79 During high-fidelity ECLS simulation scenarios, trainees must actively demonstrate cognitive, technical, and behavioral skills In addition, simulation-based training poses no risk to real patients, provides a controlled environment, and allows trainees to safely make and learn from mistakes More recently, ECLS simulation has been delivered directly to the pediatric cardiac ICU (also known as in situ simulation) and has demonstrated increased preparedness, comfort, and decreased anxiety among multidisciplinary clinical teams.80 Left Heart Decompression on Extracorporeal Life Support The majority of children with isolated, severe LV dysfunction, who are not undergoing CPR, would ideally be cannulated for left VAD support In these patients, direct cannulation of the left atrium usually provides excellent left heart decompression and additional intervention is not required However, on some occasions (e.g., in the setting of fulminant myocarditis, where rapid cannulation, and temporary pulmonary support may be required) patients may initially be placed on venoarterial ECMO Severe left heart dilation may accompany the initiation of ECMO in these patients The reason for this is that continued RV ejection results in pulmonary venous return to the left atrium, which in turn exacerbates left atrial and ventricular dilation This vicious cycle of increased wall stress, left atrial hypertension, and pulmonary venous congestion defeats one of the purposes of support, which is to rest the heart and the lungs Left heart dilation may be in part mitigated by the use of higher flows, diuretics, afterload reduction, or gentle inotropic support to encourage ejection However, this often proves inadequate, especially in the setting of LV standstill when the aortic valve remains closed In these patients, left heart decompression should be considered at the time of cannulation In children with an open sternum, decompression can be achieved by directly placing a cannula in the left atrium, which drains left atrial blood into the venous component of the extracorporeal circuit Left heart decompression can also be performed via the transcatheter route, using a blade septectomy followed by either balloon septostomy or transcatheter cannulation of the left atrium.81–83 Risks and Adverse Events During Extracorporeal Life Support Extracorporeal support carries a significant risk of hematological complications such as hemorrhage, hemolysis, and clot formation A recent report from the ELSO registry states that surgical site hemorrhage occurs in almost 30% of neonates and children supported with ECLS.3 In addition, patients on mechanical support are at significant risk of renal impairment requiring hemofiltration, arterial hypertension, and infection In addition, long-term neuromotor and cognitive outcomes may be adverse in at least half of ECLS survivors All of the risks increase the duration of mechanical support and reinforces the need for constant reassessment of circulation, timely weaning from support, and continued neurodevelopmental surveillance.84–86 Ongoing Reassessment of the Patient An important contributor to the success of ECLS is a proactive approach to reassessment once support has been established Although mechanical support can temporize an unstable patient, it is not an alternative for incomplete surgery, or a therapy for residual anatomic lesions It is widely accepted that children with residual anatomic or surgical problems do poorly unless the lesions are addressed and corrected (Fig 64.2).87 FIG 64.2 Residual lesions Aortopulmonary collateral causing failure to wean from cardiopulmonary bypass Cardiac catheterization of a patient placed on extracorporeal membrane oxygenation for inability to wean from cardiopulmonary bypass revealed a major collateral vessel (arrow) supplying the right lower lobe of the lung Role of Echocardiography for Patients on Extracorporeal Life Support Echocardiography plays an important role throughout the clinical course of infants and children receiving extracorporeal support Echocardiographic assessment of myocardial function may assist the early decision-making regarding whether or not to initiate support for a borderline patient The careful assessment of the degree of dysfunction of one or both ventricles is critical in deciding whether single ventricular support will suffice, and to decide whether VAD or ECMO would be better for the individual patient (Fig 64.3) Echocardiography is also an essential tool in assessing the degree of left (and right) heart decompression, adequacy of surgical repair, and in identifying or excluding additional surgical or anatomic defects that may be contributing to a patient's lack of response to conventional therapy